Date: Tue, 26 Feb 2019 17:57:32 +0300 From: Lev Serebryakov <lev@FreeBSD.org> To: freebsd-net@freebsd.org Subject: Can Intel 82574L (em) turn off flow control? Message-ID: <fb3b493b-109e-2b71-7509-97402086a15d@FreeBSD.org>
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This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --VUykBPKA2rgLnRlD4V63j4ElRafAUxHwy Content-Type: multipart/mixed; boundary="jkv6rRiKksA5d2MjNgeeB3dVTP3D7h4rM"; protected-headers="v1" From: Lev Serebryakov <lev@FreeBSD.org> Reply-To: lev@FreeBSD.org To: freebsd-net@freebsd.org Message-ID: <fb3b493b-109e-2b71-7509-97402086a15d@FreeBSD.org> Subject: Can Intel 82574L (em) turn off flow control? --jkv6rRiKksA5d2MjNgeeB3dVTP3D7h4rM Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable I'm seeing very strange situation when try to send a lot of traffic (with netmap pkt-gen) from 82574L to 82574L NICs. I'm using 13-CURRENT, with fc turned off (dev.em.X.fc=3D0). But still, `pkt-gen` can not send more packets per second than receiving side could process! When 82574L NIC sends to i210 NIC it could send much more than receiving side could process, and there are expected number of lost packe= ts. But when receiving side is 82574L too, `pkt-gen -f tx` shows statisitcs like this: # pkt-gen -f tx -N -4 -i em1 -l 60 -R 744000 <skipped> =2E.. 531.511259 main_thread [2464] 217104 pps (218624 pkts 104939520 bps in 1007000 usec) 429.52 avg_batch 99999 min_space 532.547259 main_thread [2464] 216958 pps (224768 pkts 107888640 bps in 1035999 usec) 426.50 avg_batch 99999 min_space 533.548256 main_thread [2464] 216872 pps (217088 pkts 104202240 bps in 1000998 usec) 426.50 avg_batch 99999 min_space =2E.. 217104 pps instead of requested 744000! Generator could generate much more if I have, say, switch on other side. Is it limitation of 82574L or bug in driver? --=20 // Lev Serebryakov --jkv6rRiKksA5d2MjNgeeB3dVTP3D7h4rM-- --VUykBPKA2rgLnRlD4V63j4ElRafAUxHwy Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEE+W0coLX0MYtnSzMK6rA8WL/cR48FAlx1U9xfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldEY5 NkQxQ0EwQjVGNDMxOEI2NzRCMzMwQUVBQjAzQzU4QkZEQzQ3OEYACgkQ6rA8WL/c R49AaQ/7BHlCIvUbSDSifp5HlaiOtz7Epddmz1nzzJ4izp5KqGLSi9CJ0AWLG/cB +TY1hAUKy8xUPfLDjZ5NKcumDs5eLtVUX9hbcEXHa1jOcfulGBb2dFzmg64ycwJC XZMhSO17MD2k363WVDmaNJPBCq7AWli0HpPGuUsMB/LCvKjlgig5QeVC1HPDA9uo ugHTnHp3BaeN/B1NCgvm7AwtNLZvFgkuifrRx8iaYOZGFIobpZBTxkzdjdhrCpDV nJVfXApgZOOMPxg96UysrTsdDS92nEJdKsrAYEkuVSfudxUfqu7IP4LgcCV7viMa 94vMyWDOY8rJB+SVVans6ZHT2HM2xuUdtGw+8Xh28A8lZjeYbFwSxXOOztUr17/A sBaCICT8FXQ1k/B2PC+mKHv6T8yxZc0lzkvv6yO9BwFCn35dTqwjWBDUFE4BDPQL s3bAyXrjihiY9Hkm3rXAoV3RaCDP6N9VkYQR0tGKYUHKis7rPwlUHORo1wgFC4na qIzIZfrybSsY2wUn2J8nT4zjntmaWG5FOm7iJKmxeZyXnrzuZt65+UZRxs01clkg QlTZad8drrudnygzUgP0lp/j35OZAPfl/hpIXRBJzLlH86Db+LOwWbILu7sDuESh 3L7+ap+NSD6+RKJLnF0hTcD2JxO61DjCSbPQIrPvsixfj7M3z5k= =FVJf -----END PGP SIGNATURE----- --VUykBPKA2rgLnRlD4V63j4ElRafAUxHwy--
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